Substrate inspection method, manufacturing method of semiconductor device and substrate inspection apparatus

ABSTRACT

A substrate inspection method includes: generating primary charged particle beams; applying the generated primary charged particle beams to an inspection target of a substrate; condensing first secondary charged particle beams including at least one of secondary charged particles, reflected charged particles, and back scattering charged particles which have been generated from the substrate, or first transmitted charged particle beams which have transmitted the inspection target, a phase difference being generated between the secondary charged particle beams or between the transmitted charged particle beams in accordance with a structure of the inspection target; imaging the secondary charged particle beams or the transmitted charged particle beams; detecting the imaged secondary charged particle beams or transmitted charged particle beams and outputting a signal of a secondary charged particle beam image or a transmitted charged particle beam image including information on the phase difference; and detecting a defect in the inspection target by use of the information on the phase difference included in the secondary charged particle beam image or the transmitted charged particle beam image.

CROSS REFERENCE TO RELATED APPLICATION

This application claims benefit of priority under 35USC .sctn.119 toJapanese patent application No. 2005-083967, filed on Mar. 23, 2005, thecontents of which are incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a substrate inspection method, amanufacturing method of a semiconductor device and a substrateinspection apparatus, and is directed to, for example, an inspection ofa substrate using a charged particle beam.

2. Related Background Art

Various techniques have been proposed wherein a rectangular electronbeam is formed by an electron gun to illuminate a substrate with theelectron beam as a primary beam, and a secondary electron, a reflectedelectron and a back scattering electron which have been generated inaccordance with variation in the shape, material and potential of thesurface of the substrate are projected as a secondary beam in anexpanded form to an electron detection unit by a map/projection opticalsystem, such that an image of the surface of a sample is obtained andthus applied to a defect inspection of a semiconductor pattern (e.g.,Japanese Patent Publication Laid-open No. 7-249393 and Japanese PatentPublication Laid-open No. 11-132975).

According to methods disclosed in these patent documents, the secondarybeams comprising the secondary electron, the reflected electron and theback scattering electron which have been generated in accordance withthe changes in the shape, material and potential of the substratesurface are imaged via the map/projection optical system, and thecontrast of a signal of this image allows the sample surface image to beformed. In such an image forming mechanism, the rate of a material of aninspection target to contribute to the contrast (material contrast) ofan obtained image is extremely high since efficiency of the secondarybeam generation depends on the material of the inspection target.Further, because the secondary beam generated from an edge portion suchas minute concave and convex shapes on the substrate surface does notcontribute to the imaging, there has been a problem that it is difficultto obtain an image contrast, and that the amount of information is smallregarding the concave and convex shapes. Moreover, the track of thegenerated secondary beam is deflected by an electric field formedimmediately on the substrate surface due to, for example, charge-up, andthus the contrast (potential contrast) of the inspection target due to asurface potential is not imaged on the detector, leading to a decreasedcontrast. There has also been a problem that if, for example, the backscattering electron is used to reduce such influence of anelectromagnetic field immediately on the surface, the influence of theelectromagnetic field immediately on the surface is indeed reduced, butalong with this, inspection sensitivity regarding the electromagneticfield itself on the substrate surface is significantly lowered.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is provideda substrate inspection method comprising:

generating a primary charged particle beam;

applying the generated primary charged particle beam to an inspectiontarget of a substrate;

condensing a first secondary charged particle beam including at leastone of secondary charged particles, reflected charged particles and backscattering charged particles which have been generated from thesubstrate, or a first transmitted charged particle beam which hastransmitted the inspection target, a phase difference being generated inthe secondary charged particle beam or in the transmitted chargedparticle beam in accordance with a structure of the inspection target;

imaging the secondary charged particle beam or the transmitted chargedparticle beam;

detecting the imaged secondary charged particle beam or transmittedcharged particle beam and outputting a signal of a secondary chargedparticle beam image or a transmitted charged particle beam imageincluding information on the phase difference; and

detecting a defect in the inspection target by use of the information onthe phase difference included in the secondary charged particle beamimage or the transmitted charged particle beam image.

According to a second aspect of the present invention, there is provideda manufacturing method of a semiconductor device comprising a substrateinspection method, said substrate inspection method including:

generating a primary charged particle beam;

applying the generated primary charged particle beam to an inspectiontarget of a substrate;

condensing a first secondary charged particle beam including at leastone of secondary charged particles, reflected charged particles and backscattering charged particles which have been generated from thesubstrate, or a first transmitted charged particle beam which hastransmitted the inspection target, a phase difference being generated inthe secondary charged particle beam or in the transmitted chargedparticle beam in accordance with a structure of the inspection target;

imaging the secondary charged particle beam or the transmitted chargedparticle beam;

detecting the imaged secondary charged particle beam or transmittedcharged particle beam and outputting a signal of a secondary chargedparticle beam image or a transmitted charged particle beam imageincluding information on the phase difference; and

detecting a defect in the inspection target by use of the information onthe phase difference included in the secondary charged particle beamimage or the transmitted charged particle beam image.

According to a third aspect of the present invention, there is provideda substrate inspection apparatus comprising:

a beam source which generates a primary charged particle beam;

an illumination unit which applies the generated primary chargedparticle beam to an inspection target;

a condensing unit which condenses a secondary charged particle beamincluding at least one of secondary charged particles, reflected chargedparticles and back scattering charged particles which have beengenerated from the inspection target, or a transmitted charged particlebeam which has transmitted the inspection target;

an imaging unit which images the secondary charged particle beam or thetransmitted charged particle beam;

a charged particle detection unit which detects the imaged secondarycharged particle beam or the imaged transmitted charged particle beam,and outputs a signal of a secondary charged particle beam image or atransmitted charged particle beam image including information on a phasedifference generated in the secondary charged particle beam or in thetransmitted charged particle beam in accordance with a structure of theinspection target; and

a signal processing unit which processes the signal of the secondarycharged particle beam image or the transmitted charged particle beamimage and outputs data on a defect in the inspection target on the basisof the information on the phase difference.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a block diagram showing a schematic configuration of asubstrate inspection apparatus according to a first embodiment of thepresent invention;

FIG. 2 is a sectional view showing one example of an inspection target;

FIG. 3 is a diagram explaining one example of a defect inspection methodaccording to a prior art as a comparative example of the presentinvention;

FIG. 4 is a sectional view showing another example of the inspectiontarget;

FIG. 5 is a diagram explaining problems of the defect inspection methodshown in FIG. 3;

FIG. 6 is a diagram explaining effects of a substrate inspection methodaccording to the first embodiment of the present invention;

FIG. 7 is a sectional view showing still another example of theinspection target;

FIG. 8 is a diagram explaining problems when the defect inspectionmethod shown in FIG. 3 is applied to the inspection target shown in FIG.7;

FIG. 9 is a diagram explaining effects when the substrate inspectionmethod according to the first embodiment of the present invention isapplied to the inspection target shown in FIG. 7;

FIG. 10 is a diagram showing one specific example of an illuminationbeam splitting unit and a map/projection beam superposing unit which areprovided in the apparatus shown in FIG. 1;

FIG. 11 is a block diagram showing a schematic configuration of asubstrate inspection apparatus according to a second embodiment of thepresent invention;

FIG. 12 is a block diagram showing a schematic configuration of asubstrate inspection apparatus according to a third embodiment of thepresent invention;

FIG. 13 is a diagram showing one specific example of a beam separatorprovided in the substrate inspection apparatus shown in FIG. 12; and

FIG. 14 is a block diagram showing a schematic configuration of asubstrate inspection apparatus according to a fourth embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention will hereinafter be described inreference to the drawings. A case will be taken up and explained belowwherein electron beams are used as charged particle beams, but thepresent invention is not limited thereto and is applicable to, forexample, ion beams and to charged particle beams other than electronssuch as an ion beam group.

(1) First Embodiment

FIG. 1 is a block diagram showing a schematic configuration of asubstrate inspection apparatus according to a first embodiment of thepresent invention. A reflective electron beam inspection apparatus 1shown in FIG. 1 comprises an electron source 10, an electron beamsplitting unit 20, an illumination unit 42, a light condensing unit 44,a beam superposing unit 50, a map/projection unit 60, an electrondetector 80 and an image processing unit 100. The present embodiment ischaracterized in that a generated primary electron beams 310 are splitinto inspection target illuminating electron beams 311 and referencetarget illuminating electron beams 312 which are applied to aninspection target TI and a reference target TR, respectively, andsecondary electron beams 315, 316 generated from the targets TI, TR aresuperposed and imaged, and then, from a signal of an obtained superposedsignal, a defect is detected in such a manner as to focus attention onthe coherency of the secondary electron beams attributed to surfacestructures of the inspection target TI and the reference target TR.

The inspection target TI is, for example, a device pattern provided onthe surface of a semiconductor substrate S (see FIG. 2) in the presentembodiment. The reference target TR is a member from which a referenceimage for defect inspection is obtained and in which the reference imageis superposed on an inspection image. In the present embodiment, thereference target TR is a pattern portion identical with the inspectiontarget TI and provided on the same inspection semiconductor substrate Stogether with the inspection target TI. When the inspection target is aperiodic pattern, an identical periodic pattern adjacent thereto or inthe vicinity thereof is used as the reference target. When the patternsfor several periods are the inspection targets, periodic patternsadjacent thereto or in the vicinity thereof for the same periods asthose of the inspection patterns are the reference targets. Even whenthe inspection target is a random pattern, an identical pattern portionof a die (chip) adjacent thereto or in the vicinity thereof is thereference target. In addition, when there exists a mirror surface partwhere no pattern exists on the same wafer, that part can be thereference target. In the present embodiment, the mirror surface partwhich can be the reference target means a part in which a difference inheight of the surface thereof is sized to an electron-opticallysufficiently negligible degree as compared with that in height of thesurface of the inspection target pattern. It is to be noted that thereference target is not limited to a surface area of an inspectionsubstrate, and that as the reference target, an arbitrary member whichis located in an arbitrary place ranging from the electron source 10 tothe beam superposing unit 60 can be set as long as it provides thereference image for defect inspection.

The electron source 10 generates primary electron beams to illuminatethe inspection target TI and the reference target TR therewith. Sincethe primary electron beams generated in the present embodiment need tohave coherency of some kind to utilize the coherency of the secondaryelectron beams, the electron source 10 preferably has as small anelectron emission surface as possible, ideally a point surface. Specificexamples of the electron source include a cold field emission electronsource having a single crystal or the like of W (tungsten), a thermalfield emission electron source having a structure in which a substancesuch as zircon oxide (ZrO₂) is applied on a W (tungsten) single-crystalchip, etc. In addition, a nano-chip having a minuscule emission surfacesuch as a carbon nano-tube (CNT) as the electron emission surface is apromising electron source for its high coherency.

The electron beam splitting unit 20 splits the generated primaryelectron beams 310 into the inspection target illuminating electronbeams 311 and the reference target illuminating electron beams 312. As atechnique to split the primary electron beams, for example, a techniqueutilizing beam deflection by an electromagnetic field is available. Morespecific splitting methods include a sector magnetic field typesplitting method using a magnetic field prism, a biprism method using anelectrostatic field, a splitting method combining the magnetic field andelectric field, etc.

The illumination unit 42 condenses the split electron beams 311 and 312to apply the same to the inspection target TI and the reference targetTR, respectively. Hereupon, if, for example, an illumination conditionfor a Koehler illumination system or the like is set by anelectromagnetic field lens, the electron beams 311 and 312 can beapplied as collimation beams to the inspection target TI and thereference target TR, respectively.

The application of the inspection target illuminating electron beams 311causes a secondary electron, a reflected electron and a back scatteringelectron to be generated from the inspection target TI, and a secondaryelectron, a reflected electron and a back scattering electron are alsogenerated from the reference target TR to which the reference targetilluminating electron beams 312 are applied. The light condensing unit44 condenses these electrons as the secondary electron beams 315, 316.The secondary electron beams 315, 316 correspond to, for example, firstand second secondary charged particle beams, respectively.

The beam superposing unit 50 superposes these secondary electron beams315, 316. The map/projection unit 60 projects the superposed secondaryelectron beams to image them on a detection surface (not shown) of theelectron detector 80. The electron detector 80 detects this image andthus transfers an image signal to the image processing unit 100. Theelectron detector 80 corresponds to, for example, a charged particledetection unit. The image processing unit 100 corresponds to, forexample, a signal processing unit, and processes the transferred imagesignal to provide inspection data on the inspection target.

Specific processing contents of the image signal by the image processingunit 100 will be explained together with the effects of defectinspection by the inspection apparatus 1 of the present embodimentreferring to FIGS. 2 to 9.

FIG. 2 is a schematic sectional view showing one example of theinspection target TI. An inspection target TI2 shown in FIG. 2 includesa plurality of line patterns P2 periodically provided on thesemiconductor substrate S and having tapered side surfaces. An abnormaldefect DF2 formed of a material different from that of the line patternsP2 exists between the two patterns on the right side of the drawing outof the line patterns P2 shown in FIG. 2.

FIG. 3 is a diagram explaining one example of a defect inspection methodaccording to a prior art. Before explaining the defect inspection methodaccording to the present embodiment, a method shown in FIG. 3 isexplained as a comparative example.

A pattern portion identical with that of the inspection target TI is setas the reference target TR to obtain its reference image RM2, and aninspection image IM2 of the inspection target TI is further obtained.Then, the image processing unit 100 calculates a difference ofgradations between the images RM2 and IM2 on a pixel-to-pixel basis, andcreates a difference gradation histogram HG2. As shown in FIG. 3, thedifference gradation histogram HG2 includes a noise component NC2 and adefect component DFC2. Here, if a threshold value Th is set on thedifference gradation histogram HG2, a prominently frequent portionexceeding the threshold value in an area of gradation value is judged asthe defect component DFC2 such that the existence of the defect DF2 canbe detected.

As in the defect DF2 shown in FIG. 2, when a film thickness isrelatively large or when it is formed of a material different from thatof the substrate surface and the patterns, the defect can be relativelyeasily detected even by the conventional inspection method. However, forexample, as in an inspection target T14 shown in FIG. 4, when the filmthickness of a defect DF4 (DF4 a, DF4 b) is very small or when it isformed of the same material as that of the underlying substrate surface,the strength of signals from the defects DF4 a, DF4 b is equal to thestrength of a signal from the substrate surface underlying the pattern,and sufficient contrast can not be obtained in the defective portion asshown in an inspection image IM4 in FIG. 5. As a result, the frequencyof a defect component DFC4 is lower in a difference gradation histogramHG4 created from the reference image RM2 and the inspection image IM4,and the defect detection is very difficult.

FIG. 6 is a diagram explaining a case where the defect inspection methodachieved by the inspection apparatus 1 of the present embodiment isapplied to the inspection target TI4 shown in FIG. 4. As shown in FIG.6, according to the defect inspection of the present embodiment, a phasedifference of the electron beams is generated in each image inaccordance with the difference in height of the surface of the parts towhich the electron beams are applied, and a interference pattern emergesin a secondary electron image to be obtained. Especially, in aninspection image IM6, information on the fine difference in height ofthe defects DF4 a, DF4 b in comparison with the surface of the substrateS is constructed as the interference pattern. This is due to the factthat the coherency of the electrons corresponding to the surface shapeof the inspection target TI4 and the reference target TR has becomeobvious, so that even when an electromagnetic field is formedimmediately on the surface of the semiconductor substrate S due to, forexample, charge-up, the information on the fine difference in heightemerges in each image.

If a difference gradation histogram HG6 is created from these imagesRM6, IM6, a strength component DFC6 can be obtained from the very thindefect DF4 formed of the same material as that of the surface of theunderlying substrate S between the patterns P2 and having a smallheight, as shown on a right side of the drawing in FIG. 6. Thus, if thethreshold value Th is set as in the conventional manner, the defect DF4can be easily detected.

Next, the defect inspection will be described when the inspection targetis a contact pattern or a via pattern (hereinafter simply referred to as“contact/via pattern”). FIG. 7 is a sectional view schematically showingan inspection target T18 comprising a contact/via pattern P4 formed inan insulating film IS to connect to an underlying wiring line WR. In theinspection target T18 shown in FIG. 7, a defect DF8 is generated whichcauses poor conduction to the underlying wiring line WR due to highresistance.

FIG. 8 is a diagram explaining problems when the defect inspectionmethod shown in FIG. 3 is applied to the inspection target TI8 shown inFIG. 7, as a comparative example of a substrate inspection method of thepresent embodiment. As shown in an inspection image IM8 in the center ofthe drawing of FIG. 8, a potential contrast generated by a surfacepotential is low in an electron beam image, and it is thus impossible toobtain sufficient contrast for the defect DF8. As a result, thefrequency of a defect component DFC8 is low in a difference gradationhistogram HG8 as shown on the right side of the drawing of FIG. 8, andthe defect detection has heretofore been difficult.

FIG. 9 is a diagram explaining a case where the defect inspection methodachieved by the inspection apparatus 1 of the present embodiment isapplied to the inspection target TI8 shown in FIG. 7. On the surface ofthe defect DF8, the electric field is subtly changed due to irradiationof the primary electron beams and the phase difference between theelectron beams is produced due to this change. Therefore, according tothe substrate inspection of the present embodiment, the interferencepattern in the defect DF8 is changed and becomes obvious in the image insuch a manner as to be apparently different from the interferencepatterns in other normal parts, as shown in an inspection image IM10 inthe center of FIG. 9. The use of such a difference in the interferencepatterns makes it possible to easily detect a defect component DFC10 ona difference gradation histogram HG10, as shown on the right side of thedrawing of FIG. 9.

Here, a specific configuration example of the electron beam splittingunit 20 and the beam superposing unit 50 provided in the substrateinspection apparatus 1 shown in FIG. 1 will be described. FIG. 10 is ablock diagram including the electron beam splitting unit 20 and the beamsuperposing unit 50 using an electrostatic biprism. It is to be notedthat the map/projection unit 60 is omitted in FIG. 10 for simplificationof explanation.

The electron beam splitting unit 20 includes a line electrode 22connected to a power source 26, and parallel plane-type electrodes 24 a,24 b oppositely arranged to sandwich the line electrode 22. As shown inFIG. 10, while the parallel plane electrodes 24 a, 24 b are grounded, anegative voltage is applied to the line electrode 22 from the powersource 26, such that the primary electron beams 310 can be split intotwo directions by electrostatic fields generated between the lineelectrode 22 and the parallel plane electrode 24 a and between the lineelectrode 22 and the parallel plane electrode 24 b, respectively. In thesame manner, the beam superposing unit 50 is also constructed using theelectrostatic biprism, and includes a line electrode 52 connected to apower source 56, and parallel plane electrodes 54 a, 54 b oppositelyarranged to sandwich the line electrode 52. While the parallel planeelectrodes 54 a, 54 b are grounded, a positive voltage is applied to theline electrode 52 from the power source 56, such that the secondaryelectron beams 315, 316 generated from the inspection target TI and thereference target TR, respectively, are superposed by electrostaticfields generated between the line electrode 52 and the parallel planeelectrode 54 a and between the line electrode 52 and the parallel planeelectrode 54 b, respectively.

As methods of splitting and superposing the beams, if a use is made of,in addition to the example shown in FIG. 10, a prism utilizingdeflection by the magnetic field and deflection by an electromagneticfield deflecting field in which the magnetic field and electric fieldare mixed, similar effects can be expected.

(2) Second Embodiment

FIG. 11 is a block diagram showing a schematic configuration of asubstrate inspection apparatus according to a second embodiment of thepresent invention. A substrate inspection apparatus 3 shown in FIG. 11comprises an electron beam expansion unit 30 and a collimation unit 46instead of the electron beam splitting unit 20 and the illumination unit42 provided in the substrate inspection apparatus 1 shown in FIG. 1. Thesubstrate inspection apparatus 3 does not split primary electron beams310 generated by an electron source 10 into inspection targetilluminating electron beams 311 and reference target illuminatingelectron beams 312. The substrate inspection apparatus 3, however, formsillumination beams 320 with a large illumination area, simultaneouslyilluminates both an inspection target and a reference target with theillumination beams 320 collimated in the collimation unit 46,maps/projects, in a map/projection unit 60, a secondary electron, areflected electron and a back scattering electron generated from targetparts as secondary electron beams 315, 316, and superposes them in abeam superposing unit 50 to image them on a detection surface (notshown) of an electron detector 80, thereby detecting a signal of anelectron beam image including interference patterns and processing it inan image processing unit 100. The inspection method of the presentembodiment is suitable for the inspection of, for example, a memorypattern in which semiconductor patterns are periodically arranged, andallows the inspection of the inspection target every few periods. Thisis an approach called a cell to cell method in a defect inspectiontechnique. Since the degree of integration is extremely high in a memorycell of a semiconductor pattern reaching a submicron level, it is enoughfor the inspection target of several periods to be illuminated in anarea of several μm with the illumination beams. Therefore, a less burdenis imposed on the electron beam expansion unit 30, and it is thuspossible for the electron beam expansion unit 30 to also serve as thecollimation unit 46.

(3) Third Embodiment

FIG. 12 is a block diagram showing a schematic configuration of asubstrate inspection apparatus according to a third embodiment of thepresent invention. A substrate inspection apparatus 5 shown in FIG. 12is characterized in that it comprises a beam separator 140 and anillumination/condensation unit 150 instead of the illumination unit 42and the light condensing unit 44 provided in the substrate inspectionapparatus 1 shown in FIG. 1, and in that an inspection substrate isvertically illuminated by inspection target illuminating electron beams311 and reference target illuminating electron beams 312 split fromprimary electron beams 310 by an electron beam splitting unit 20. Thesubstrate inspection apparatus 5 in other parts is substantially thesame as the substrate inspection apparatus 1 shown in FIG. 1. Asecondary electron, a reflected electron and a back scattering electrongenerated from an inspection target TI and a reference target TR on theinspection substrate are condensed by the illumination/condensation unit150 to become secondary electron beams 315, 316, which are deflected inthe beam separator 140, and then superposed by a beam superposing unit50 and projected by a map/projection unit 60, thus being imaged on adetection surface (not shown) of an electron detector 80.

One example of the beam separator 140 is shown in FIG. 13. The beamseparator 140 shown in FIG. 13 comprises parallel plane electrodes 142a, 142 b connected to power sources 144 a, 144 b, respectively, andoppositely arranged magnetic poles 146 a, 146 b connected to powersources 148 a, 148 b, respectively. The beam separator 140 orients anelectric field excited by the parallel plane electrodes 142 a, 142 b anda magnetic field excited by the magnetic poles 146 a, 146 bperpendicular to each other (forms an E×B field) to deflect incidentillumination beams so that they vertically enter the inspectionsubstrate. On the other hand, the beam separator 140 linearly moves, inthe E×B field, the secondary electron, the reflected electron and theback scattering electron which have been generated from the inspectiontarget TI and the reference target TR on the inspection substrate andwhich come in from a direction opposite to that of the illuminationbeams. Thus, the illumination beams 311, 312 and the secondary electronbeams 315, 316 can be separated from each other. The illumination beamsand the secondary electron beams can be separated not only by such amethod using the E×B field but also by a sector magnetic field.

(4) Fourth Embodiment

FIG. 14 is a block diagram showing a schematic configuration of asubstrate inspection apparatus according to a fourth embodiment of thepresent invention. A substrate inspection apparatus 7 shown in FIG. 14is one example of a transmitted electron beam inspection apparatus, andsuitable for defect inspection of an EB exposure mask such as a CP maskor an LEEPLE mask. The substrate inspection apparatus 7 comprises anelectron source 710, an electron beam illumination unit 720, an electronbeam splitting unit 730, a light condensing unit 740, a transmitted beamsuperposing unit 770, an imaging unit 780, an electron image detectionunit 790 and an inspection image processing unit 800. The substrateinspection apparatus 7 superposes electron beams 912, 911 transmitted aninspection target TI and a reference target TR in the same mask,respectively, in the transmitted beam superposing unit 770, and thenimage them in the electron image detection unit 790, thereby making itpossible to obtain a transmitted beam image including interferencepatterns. Specific functions of components and an inspection method ofthe present embodiment are substantially the same as those in the firstembodiment, and therefore, redundant explanations are omitted here.

(5) Manufacturing Method of Semiconductor Device

If the substrate inspection methods in the embodiments described aboveare incorporated into a manufacturing method of a semiconductor device,a substrate surface can be inspected for faults and defects with highsensitivity, and it is therefore possible to manufacture a semiconductordevice with a high yield.

While some of the embodiments of the present invention have beendescribed above, the present invention is not limited to the embodimentsdescribed above, and it should be understood that various modificationscan be made and applied within the scope thereof. A interference patternimage of an inspection part and a interference pattern image of areference part are obtained and compared with each other in theembodiments described above, but when it is possible to create areference interference pattern from, for example, design data onsoftware, the interference pattern image of the inspection part alonemay be obtained and compared therewith.

1. A substrate inspection method comprising: generating primary chargedparticle beams; applying the generated primary charged particle beams toan inspection target of a substrate; condensing secondary chargedparticle beams including first secondary charged particle beams, eachhaving at least one of secondary charged particles, reflected chargedparticles, and back scattering charged particles which have beengenerated from the substrate, or transmitted charged particle beamsincluding first transmitted charged particle beams which have beentransmitted through the inspection target, a phase difference beinggenerated between the secondary charged particle beams or between thetransmitted charged particle beams in accordance with a structure of theinspection target; imaging the secondary charged particle beams or thetransmitted charged particle beams; detecting the imaged secondarycharged particle beams or transmitted charged particle beams andoutputting a signal of a secondary charged particle beam image or atransmitted charged particle beam image including information on thephase difference; and detecting a defect in the inspection target by useof the information on the phase difference included in the secondarycharged particle beam image or the transmitted charged particle beamimage.
 2. The substrate inspection method according to claim 1, furthercomprising: splitting the generated primary charged particle beams intoa plurality of beam fluxes; applying a part of the split beam fluxes toa reference target; condensing second secondary charged particle beams,each including at least one of secondary charged particles, reflectedcharged particles and back scattering charged particles which have beengenerated from the reference target, or second transmitted chargedparticle beams which have transmitted the reference target; andsuperposing the first secondary charged particle beams and the secondsecondary charged particle beams or superposing the first transmittedcharged particle beams and the second transmitted charged particlebeams, wherein the imaged secondary charged particle beams or the imagedtransmitted charged particle beams are constituted of the superposedfirst and second secondary charged particle beams or the superposedfirst and second transmitted charged particle beams, and the phasedifferences are generated between the first secondary charged particlebeams and between the second secondary charged particle beams,respectively, or the phase differences are generated between the firsttransmitted charged particle beams and between the second transmittedcharged particle beams, respectively, in accordance with the structuresof the inspection target and the reference target.
 3. The substrateinspection method according to claim 2, wherein at least one of thesplitting of the primary charged particle beams and superposition of thesecondary charged particle beams is performed by use of an electrostaticfield deflecting field.
 4. The substrate inspection method according toclaim 2, wherein at least one of the splitting of the primary chargedparticle beams and superposition of the secondary charged particle beamsis performed by use of a magnetic field deflecting field.
 5. Thesubstrate inspection method according to claim 2, wherein at least oneof the splitting of the primary charged particle beams and superpositionof the secondary charged particle beams is performed by use of anelectromagnetic field deflecting field.
 6. The substrate inspectionmethod according to claim 2, wherein the split beam fluxes arecollimated to irradiate the inspection target and the reference target,respectively.
 7. The substrate inspection method according to claim 2,wherein the split beam fluxes substantially vertically irradiate theinspection target and the reference target, respectively.
 8. Thesubstrate inspection method according to claim 1, further comprising:expanding cross sectional areas of the beam fluxes of the primarycharged particle beams so that the primary charged particle beamsirradiate the inspection target and a reference target; collimating theexpanded beam fluxes to apply the same to the inspection target and thereference target; condensing second secondary charged particle beamsincluding at least one of secondary charged particles, reflected chargedparticles and back scattering charged particles which have beengenerated from the reference target, or second transmitted chargedparticle beams which have transmitted the reference target; andsuperposing the first secondary charged particle beams and the secondsecondary charged particle beams or superposing the first transmittedcharged particle beams and the second transmitted charged particlebeams, wherein the imaged secondary charged particle beams ortransmitted charged particle beams are constituted of the superposedfirst and second secondary charged particle beams or the superposedfirst and second transmitted charged particle beams, and phasedifferences are generated between the first secondary charged particlebeams and second secondary charged particle beams, respectively, orphase differences are generated between the first transmitted chargedparticle beams and between the second transmitted charged particlebeams, respectively, in accordance with the structures of the inspectiontarget and the reference target.
 9. The substrate inspection methodaccording to claim 1, further comprising: creating a reference targetfrom design data on the inspection target, and creating, by operationprocessing, a secondary charged particle beam image of the referencetarget or a transmitted charged particle beam image of the referencetarget which is obtained when the primary charged particle beams areapplied to the reference target, wherein detecting the defect in theinspection target includes using the secondary charged particle beamimage or the transmitted charged particle beam image of the referencetarget as an inspection standard.
 10. A manufacturing method of asemiconductor device comprising a substrate inspection method, saidsubstrate inspection method including: generating primary chargedparticle beams; applying the generated primary charged particle beams toan inspection target of a substrate; condensing secondary chargedparticle beams including first secondary charged particle beams, eachhaving at least one of secondary charged particles, reflected chargedparticles and back scattering charged particles which have beengenerated from the substrate, or transmitted charged particle beamsincluding first transmitted charged particle beams which have beentransmitted through the inspection target, a phase difference beinggenerated between the secondary charged particle beams or between thetransmitted charged particle beams in accordance with a structure of theinspection target; imaging the secondary charged particle beams or thetransmitted charged particle beams; detecting the imaged secondarycharged particle beams or transmitted charged particle beams andoutputting a signal of a secondary charged particle beam image or atransmitted charged particle beam image including information on thephase difference; and detecting a defect in the inspection target by useof the information on the phase difference included in the secondarycharged particle beam image or the transmitted charged particle beamimage.
 11. The manufacturing method of a semiconductor device accordingto claim 10, further comprising: splitting the generated primary chargedparticle beams into a plurality of beam fluxes; applying a part of thesplit beam fluxes to a reference target; condensing second secondarycharged particle beams, each including at least one of secondary chargedparticles, reflected charged particles and back scattering chargedparticles which have been generated from the reference target, or secondtransmitted charged particle beams which have transmitted the referencetarget; and superposing the first secondary charged particle beams andthe second secondary charged particle beams or superposing the firsttransmitted charged particle beams and the second transmitted chargedparticle beams, wherein the imaged secondary charged particle beams orthe imaged transmitted charged particle beams are constituted of thesuperposed first and second secondary charged particle beams or thesuperposed first and second transmitted charged particle beams, and thephase differences are generated between the first secondary chargedparticle beams and between the second secondary charged particle beams,respectively, or the phase differences are generated between the firsttransmitted charged particle beams and between the second transmittedcharged particle beams, respectively, in accordance with the structuresof the inspection target and the reference target.
 12. The manufacturingmethod of a semiconductor device according to claim 11, wherein thesplit beam fluxes substantially vertically irradiate the inspectiontarget and the reference target, respectively.
 13. The manufacturingmethod of a semiconductor device according to claim 10, furthercomprising: creating a reference target from design data on theinspection target, and creating, by operation processing, a secondarycharged particle beam image of the reference target or a transmittedcharged particle beam image of the reference target which is obtainedwhen the primary charged particle beams are applied to the referencetarget, wherein detecting the defect in the inspection target includesusing the secondary charged particle beam image or the transmittedcharged particle beam image of the reference target as an inspectionstandard.
 14. A substrate inspection apparatus comprising: a beam sourcewhich generates primary charged particle beams; an illumination unitwhich applies the generated primary charged particle beams to aninspection target; a condensing unit which condenses secondary chargedparticle beams including at least one of secondary charged particles,reflected charged particles and back scattering charged particles whichhave been generated from the inspection target, or transmitted chargedparticle beams which have transmitted the inspection target; an imagingunit which images the secondary charged particle beams or thetransmitted charged particle beams; a charged particle detection unitwhich detects the imaged secondary charged particle beams or the imagedtransmitted charged particle beams, and outputs a signal of a secondarycharged particle beam image or a transmitted charged particle beam imageincluding information on a phase difference generated between thesecondary charged particle beams or between the transmitted chargedparticle beams in accordance with a structure of the inspection target;and a signal processing unit which processes the signal of the secondarycharged particle beam image or the transmitted charged particle beamimage and outputs data on a defect in the inspection target on the basisof the information on the phase difference.
 15. The substrate inspectionapparatus according to claim 14, further comprising: a charged particlebeam splitting unit which splits the generated primary charged particlebeams into a plurality of beam fluxes; and a charged particle beamsuperposing unit which superposes the split beam fluxes, wherein theillumination unit applies a part of the beam fluxes split by the chargedparticle beam splitting unit to a reference target, the condensing unitcondenses second secondary charged particle beams, each of the secondsecondary charged particle beams includes at least one of secondarycharged particles, reflected charged particles and back scatteringcharged particles which have been generated from the reference target,or second transmitted charged particle beams which have transmitted thereference target, the charged particle beam superposing unit superposesthe first secondary charged particle beams and the second secondarycharged particle beams or superposes the first transmitted chargedparticle beams and the second transmitted charged particle beams, theimaged secondary charged particle beams or transmitted charged particlebeams is constituted of the superposed first and second secondarycharged particle beams or the superposed first and second transmittedcharged particle beams, and the phase differences are generated betweenthe first secondary charged particle beams and between the secondsecondary charged particle beams, respectively, or phase differences aregenerated between the first transmitted charged particle beams andbetween the second transmitted charged particle beams, respectively, inaccordance with the structures of the inspection target and thereference target.
 16. The substrate inspection apparatus according toclaim 15, wherein the charged particle beam splitting unit includes aprism utilizing deflection by an electrostatic field.
 17. The substrateinspection apparatus according to claim 15, wherein the charged particlebeam splitting unit includes a prism utilizing deflection by a magneticfield.
 18. The substrate inspection apparatus according to claim 15,wherein the charged particle beam splitting unit includes a prismutilizing deflection by an electromagnetic field deflecting field inwhich a magnetic field and an electric field are mixed.
 19. Thesubstrate inspection apparatus according to claim 14, furthercomprising: a charged particle beam expansion unit which expands crosssectional areas of the beam fluxes of the primary charged particle beamsso that the primary charged particle beams irradiate the inspectiontarget and a reference target; and a collimator which collimates theexpanded beam fluxes to apply the same to the inspection target and thereference target; a charged particle beam superposing unit whichsuperposes the first secondary charged particle beams and secondsecondary charged particle beams or superposes the first transmittedcharged particle beams and second transmitted charged particle beams,the second secondary charged particle beams including at least one ofsecondary charged particles, reflected charged particles and backscattering charged particles which have been generated from thereference target, the second secondary charged particle beams beingcondensed by the condensing unit, the second transmitted chargedparticle beams having transmitted the reference target, and the secondtransmitted charged particle beams being condensed by the condensingunit; wherein the imaged secondary charged particle beams or transmittedcharged particle beams are constituted of the superposed first andsecond secondary charged particle beams or the superposed first andsecond transmitted charged particle beams, and the phase differences aregenerated between the first secondary charged particle beams and secondsecondary charged particle beams, respectively, or the phase differencesare generated between the first transmitted charged particle beams andbetween the second transmitted charged particle beams, respectively, inaccordance with the structures of the inspection target and thereference target.
 20. The substrate inspection apparatus according toclaim 15, wherein the illumination unit and the condensing unit deflectthe primary charged particle beams so that the beam fluxes substantiallyvertically irradiate the inspection target and the reference target,respectively.
 21. The substrate inspection method according to claim 1,wherein the information in the secondary charged particle beam image orthe transmitted charged particle beam image includes an interferencepattern due to the phase difference.
 22. The substrate inspectionapparatus according to claim 14, wherein the information in thesecondary charged particle beam image or the transmitted chargedparticle beam image includes an interference pattern due to the phasedifference.